foams up the nutrient rich coastal water
- Size
- Height: 5–15 cm
- Lifespan
- 1–2 years
- Diet
- Photosynthetic. Draws energy from sunlight and nutrients from surrounding water. Requires clean water and good flow.
- Habitat
- The sea foam algae grows in open coastal waters throughout New Zealand – from Northland down to Stewart Island, particularly in the spring and summer when the water warms and the nutrients are abundant. It is a creature of the bloom, the surge, the places where the sea turns to foam. It forms floating colonies of microscopic cells that create thick, white, frothy foam on the surface of the water. It looks harmless, like sea foam or whipped cream. But it is not always harmless.
- Range
- New Zealand - found throughout the North and South Islands in sheltered bays, rock pools, and estuaries. Most common in lowland coastal waters with high nutrient levels.
- Endemism
- Native
- Main Threats
- None significant - this species is common and widespread in nutrient-rich waters. Localised threats include coastal development and pollution. Classified as Not Threatened.
- Population
- Not Threatened, but it can cause problems when it blooms. Sea foam algae is naturally present in New Zealand waters, but it can form dense blooms under the right conditions – warm water, still weather, and high nutrient levels. These blooms can be large, covering hectares of sea surface. It is not rare. It is just very, very foamy.
- Conservation Status
- Not Threatened
- Human Risk
- poisonous
- Handling Note
- produces toxic foam in bloom conditions, causes skin and respiratory irritation
- Conservation Note
- Native microalgae; not assessed by NZTCS as marine/planktonic algae are outside the scope of current threat classifications.
- Te Ao Māori
- No recorded Māori name distinguishes the sea foam algae from other sea foams. The foam would have been seen. But its cause would have been a mystery. A sign that the sea was changing. That the season was turning. That something was happening beneath the surface. The white foam on the water was a sign of spring. Of warmer weather. Of the sea waking up after the winter. But it was also a warning. The foam could be irritating. The water could be sick. Today, the sea foam algae still blooms in the coastal waters of New Zealand. You can see it in the spring. A thick white scum on the surface. You can watch the foam blow across the water. Wash up on the beach. Fade away. It is the foamy one. The harmless-looking one. The one that reminds us that the sea is full of surprises. It has been here for millions of years. It will be here as long as the sea still foams.
You have seen it. Thick, white, frothy scum on the surface of the water. Like someone poured detergent into the sea. Phaeocystis globosa is the one that turns the sea to foam. The foam is made of millions of microscopic colonies. Each one a sphere of cells embedded in a gel-like matrix. When the colonies break apart, they release the gel. Which mixes with the water and the air to form foam. What makes it special? The foam. The foam can be metres thick. Drifting across the surface of the sea. Washing up on beaches like a white blanket. It is soft and fluffy. Like whipped cream or meringue. Children love to play in it. But it has a dark side.
The sea foam algae produces a chemical called dimethylsulfoniopropionate (DMSP). Which breaks down into dimethyl sulfide (DMS). The gas that gives the sea its distinctive, salty smell. DMS also plays a role in cloud formation. Seeding the sky with particles that water vapour can condense around. The sea foam algae is not just a nuisance. It is a player in the global climate. When the sea foam algae blooms, it can cause problems. The foam can be irritating to the skin and eyes. When the bloom dies and decays, it uses up oxygen in the water. Creating dead zones. Some blooms produce toxins that can harm fish and other marine life. It looks harmless. But it is not always harmless. Biologically, the sea foam algae is a haptophyte. A type of planktonic alga. It reproduces by cell division. Forming colonies that can grow rapidly under ideal conditions. The sea foam algae is a reminder that the sea is not just water and waves. It is alive with microscopic creatures. Creatures that can turn the sea to foam. That can change the climate. That can be beautiful and dangerous at the same time. Not Threatened, but it can cause problems when it blooms. Sea foam algae is naturally present in New Zealand waters. But it can form dense blooms under the right conditions. Warm water. Still weather. High nutrient levels. These blooms can be large. Covering hectares of sea surface. It is not rare. It is just very, very foamy.